U.S. patent application number 16/559644 was filed with the patent office on 2020-11-05 for thermal runaway detection circuit and method.
This patent application is currently assigned to Contemporary Amperex Technology Co., Limited. The applicant listed for this patent is Contemporary Amperex Technology Co., Limited. Invention is credited to Zhimin Dan, Yizhen Hou, Guoliang Hu, Xiao WANG, Jia Xu, Chao Zeng, Wei Zhang.
Application Number | 20200348365 16/559644 |
Document ID | / |
Family ID | 1000004331474 |
Filed Date | 2020-11-05 |
![](/patent/app/20200348365/US20200348365A1-20201105-D00000.png)
![](/patent/app/20200348365/US20200348365A1-20201105-D00001.png)
![](/patent/app/20200348365/US20200348365A1-20201105-D00002.png)
![](/patent/app/20200348365/US20200348365A1-20201105-D00003.png)
![](/patent/app/20200348365/US20200348365A1-20201105-D00004.png)
United States Patent
Application |
20200348365 |
Kind Code |
A1 |
WANG; Xiao ; et al. |
November 5, 2020 |
THERMAL RUNAWAY DETECTION CIRCUIT AND METHOD
Abstract
The disclosure provides a thermal runaway detection circuit and
method, and relates to batteries. The thermal runaway detection
circuit includes: a sensing module including a sensing cable; a
detection module connected to the sensing cable and including at
least one set of voltage dividing resistors; a processing module
connected to the detection module, wherein the processing module is
configured to obtain thermal runaway detection data, and determine
whether thermal runaway occurs in the battery pack based on the
thermal runaway detection data, wherein the thermal runaway
detection data includes battery pack data and sampled data
collected from sampling points, and the sampling points are
disposed between the two connected voltage dividing resistor sets.
The technical solutions in the present disclosure can improve
safety of the battery pack.
Inventors: |
WANG; Xiao; (Ningde City,
CN) ; Zeng; Chao; (Ningde City, CN) ; Xu;
Jia; (Ningde City, CN) ; Dan; Zhimin; (Ningde
City, CN) ; Hou; Yizhen; (Ningde City, CN) ;
Zhang; Wei; (Ningde City, CN) ; Hu; Guoliang;
(Ningde City, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Contemporary Amperex Technology Co., Limited |
Ningde City |
|
CN |
|
|
Assignee: |
Contemporary Amperex Technology
Co., Limited
Ningde City
CN
|
Family ID: |
1000004331474 |
Appl. No.: |
16/559644 |
Filed: |
September 4, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02J 7/0029 20130101;
H01M 2010/4271 20130101; G01K 3/005 20130101; G01R 31/392 20190101;
H01M 10/425 20130101; G01K 3/10 20130101; G01R 31/3842 20190101;
G01K 13/00 20130101; H01M 10/48 20130101 |
International
Class: |
G01R 31/392 20060101
G01R031/392; H02J 7/00 20060101 H02J007/00; G01R 31/3842 20060101
G01R031/3842; G01K 3/00 20060101 G01K003/00; G01K 3/10 20060101
G01K003/10; G01K 13/00 20060101 G01K013/00; H01M 10/48 20060101
H01M010/48; H01M 10/42 20060101 H01M010/42 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 30, 2019 |
CN |
201910362174.5 |
Claims
1. A thermal runaway detection circuit, characterized by
comprising: a sensing module including a sensing cable, wherein a
distance between at least a portion of the sensing cable and a cell
of a battery pack is less than a temperature sensitive distance
threshold; a detection module connected to the sensing cable and
including at least one set of voltage dividing resistors, wherein
one end of each set of voltage dividing resistors is connected to a
first power supply terminal, and the other end of each set of
voltage dividing resistors is connected to the ground, and each set
of voltage dividing resistors includes at least two voltage
dividing resistor sets connected in series; a processing module
connected to the detection module, wherein the processing module is
configured to obtain thermal runaway detection data, and determine
whether thermal runaway occurs in the battery pack based on the
thermal runaway detection data, wherein the thermal runaway
detection data includes battery pack data and sampled data
collected from sampling points, and the sampling points are
disposed between the two connected voltage dividing resistor
sets.
2. The thermal runaway detection circuit of claim 1, wherein the
sensing cable includes a first sensing cable and a second sensing
cable disposed on a circuit board above the battery pack, at least
a portion of the first sensing cable and at least a portion of the
second sensing cable are disposed right above a cell
explosion-proof valve port of the cell of the battery pack.
3. The thermal runaway detection circuit of claim 2, wherein the
detection module includes two sets of voltage dividing resistors,
the sampling points include a first sampling point, a second
sampling point, a third sampling point, and a fourth sampling
point; wherein a first set of voltage dividing resistors includes a
first voltage dividing resistor set, a second voltage dividing
resistor set, and a third voltage dividing resistor set connected
in series, one end of the first voltage dividing resistor set is
connected to the first power supply terminal, one end of the third
voltage dividing resistor set is connected to the ground, the first
sampling point is disposed between the first voltage dividing
resistor set and the second voltage dividing resistor set, the
second sampling point is disposed between the second voltage
dividing resistor set and the third voltage dividing resistor set,
one end of the first sensing cable is connected to the first
sampling point, and the other end of the first sensing cable is
connected to the second sampling point; and wherein the second set
of voltage dividing resistors includes a fourth voltage dividing
resistor set, a fifth voltage dividing resistor set and a sixth
voltage dividing resistor set connected in series, one end of the
fourth voltage dividing resistor set is connected to the first
power supply terminal, one end of the sixth voltage dividing
resistor set is connected to the ground, the third sampling point
is disposed between the fourth voltage dividing resistor set and
the fifth voltage dividing resistor set, the fourth sampling point
is disposed between the fifth voltage dividing resistor set and the
sixth voltage dividing resistor set, one end of the second sensing
cable is connected to the third sampling point, and the other end
of the second sensing cable is connected to the fourth sampling
point.
4. The thermal runaway detection circuit of claim 3, wherein the
processing module is configured to: obtain a first sampled data, a
second sampled data, a third sampled data, and a fourth sampled
data from the first sampling point, the second sampling point, the
third sampling point, and the fourth sampling point, respectively;
determine an on-off state of the first sensing cable based on the
first sampled data and the second sampled data; determine an on-off
state of the second sensing cable based on the third sampled data
and the fourth sampled data; and determine whether thermal runaway
occurs in the battery pack based on the on-off state of the first
sensing cable, the on-off state of the second sensing cable, and
the battery pack data.
5. The thermal runaway detection circuit of claim 4, wherein the
processing module is configured to: determine that the first
sensing cable is open circuited when the first sampled data is
within a first open-circuit threshold range and the second sampled
data is within a second open-circuit threshold range; determine
that the second sensing cable is open circuited when the third
sampled data is within a third open-circuit threshold range and the
fourth sampled data is within a fourth open-circuit threshold
range; and determine that thermal runaway occurs in the battery
pack when the first sensing cable and the second sensing cable are
open circuited and at least one parameter of the battery pack data
satisfies a fault condition within a preset period, the battery
pack data comprising the at least one parameter.
6. The thermal runaway detection circuit of claim 5, wherein the
processing module is configured to: determine that thermal runaway
occurs in the battery pack, when it is determined that at least one
of the first sensing cable and the second sensing cable is not open
circuited and at least one set of parameters of the battery pack
data satisfies a fault condition within a preset period, the set of
parameters comprising at least two parameters.
7. The thermal runaway detection circuit of claim 6, wherein the
processing module is further configured to: send a thermal runaway
warning message, when it is determined that at least one of the
first sensing cable and the second sensing cable is not open
circuited and the battery pack data satisfies a fault condition,
wherein the battery pack data includes a maximum voltage of a cell
in the battery pack during charging, an actual state of charge of
the battery pack during charging, and a charging current of the
battery pack during charging; and wherein the fault condition
includes a parameter exceeding a safety parameter threshold
range.
8. The thermal runaway detection circuit of claim 1, wherein the
sensing cable includes a third sensing cable disposed in a shield
above the battery pack, and at least a portion of the third sensing
cable is disposed right above a cell explosion-proof valve port of
the cell of the battery pack.
9. The thermal runaway detection circuit of claim 8, wherein the
third sensing cable is a tin wire and the shield is a mica
board.
10. The thermal runaway detection circuit of claim 8, wherein the
detection module comprises a set of voltage dividing resistors, and
the sampling points includes a fifth sampling point; and wherein
the set of voltage dividing resistors includes a seventh voltage
dividing resistor set and an eighth voltage dividing resistor set
connected in series through the third sensing cable, one end of the
seventh voltage dividing resistor set is connected to the first
power supply terminal, one end of the eighth voltage dividing
resistor set is connected to the ground, and the fifth sampling
point is disposed between the seventh voltage dividing resistor set
and the eighth voltage dividing resistor set.
11. The thermal runaway detection circuit of claim 8, wherein the
processing module is configured to: obtain a fifth sampled data
from the fifth sampling point; determine an on-off state of the
third sensing cable based on the fifth sampled data; determine
whether thermal runaway occurs in the battery pack based on the
on-off state of the third sensing cable and the battery pack
data.
12. The thermal runaway detection circuit of claim 11, wherein the
processing module is configured to: determine that the third
sensing cable is open circuited when the fifth sampled data is
within a fifth open-circuit threshold range; determine that thermal
runaway occurs in the battery pack when the third sensing cable is
open circuited and at least one parameter of the battery pack data
satisfies a fault condition within a preset period, the battery
pack data comprising the at least one parameter.
13. The thermal runaway detection circuit of claim 12, wherein the
processing module is configured to: determine that thermal runaway
occurs in the battery pack when the third sensing cable is not open
circuited and at least one set of parameters of the battery pack
data satisfies a fault condition within a preset period, the set of
parameters comprising at least two parameters.
14. The thermal runaway detection circuit of claim 5, wherein the
battery pack data comprises one or more of: a maximum temperature
of a cell in the battery pack, a temperature change rate of a cell
in the battery pack, a difference between the maximum temperature
and a minimum temperature of a cell in the battery pack, a minimum
voltage of a cell in the battery pack, a number of voltage sampling
open-circuit faults of the battery pack, a temperature sensing
failure parameter, and a cell monitoring communication failure
parameter, wherein the fault condition includes a parameter
exceeding a safety parameter threshold range or a parameter
characterizing a failure.
15. The thermal runaway detection circuit of claim 6, wherein the
set of parameters comprises any set of the following sets of
parameters: a minimum voltage of a cell in the battery pack, and a
maximum temperature of a cell in the battery pack; the minimum
voltage of a cell in the battery pack, and a temperature change
rate of a cell in the battery pack; the minimum voltage of a cell
in the battery pack, and a difference between the maximum
temperature of a cell in the battery pack and a minimum temperature
of a cell in the battery pack; the temperature change rate of a
cell in the battery pack, and the maximum temperature of a cell in
the battery pack; the temperature change rate of a cell in the
battery pack, and the difference between the maximum temperature of
a cell in the battery pack and the minimum temperature of a cell in
the battery pack; a number of voltage sampling open-circuit faults
of the battery pack, and the maximum temperature of a cell in the
battery pack; the number of voltage sampling open-circuit faults of
the battery pack, and the temperature change rate of a cell in the
battery pack; the number of voltage sampling open-circuit faults of
the battery pack, and the difference between the maximum
temperature of a cell in the battery pack and the minimum
temperature of a cell in the battery pack; and the number of
voltage sampling open-circuit faults of the battery pack, and a
temperature sensing failure parameter, wherein the fault condition
includes a parameter exceeding a safety parameter threshold range
or a parameter characterizing a failure.
16. The thermal runaway detection circuit of claim 12, wherein the
processing module is further configured to: send a thermal runaway
warning message, when it is determined that the third sensing cable
is not open circuited and the battery pack data satisfies a fault
condition, wherein the battery pack data includes a maximum voltage
of a cell in the battery pack during charging, an actual state of
charge of the battery pack during charging, and a charging current
of the battery pack during charging; and wherein the fault
condition includes a parameter exceeding a safety parameter
threshold range.
17. The thermal runaway detection circuit of claim 1, further
comprising: a sleep-wakeup module disposed between the first power
supply terminal and all sets of voltage dividing resistors, and the
sleep-wakeup module is configured to send a control signal to a
power module of the battery management unit when the battery
management unit is in a sleep state, wherein the control signal is
configured to instruct the power module to control the battery
management unit to remain in the sleep state or switch to an
operating state.
18. The thermal runaway detection circuit of claim 18, wherein: the
sleep-wakeup module includes a ninth voltage dividing resistor set,
or the sleep-wakeup module includes a ninth voltage dividing
resistor set and a diode, an anode of the diode is connected to the
ninth voltage dividing resistor set, and a cathode of the diode is
connected to the power module.
19. The thermal runaway detection circuit of claim 1, wherein: the
detection module further includes a protection capacitor, one end
of the protection capacitor is connected to one end of a voltage
dividing resistor set connected to a sampling point, and the other
end of the protection capacitor is connected to the ground, the
detection module further includes a filter capacitor and a filter
resistor, one end of the filter capacitor is connected to one end
of the filter resistor and the sampling point, and the other end of
the filter capacitor is connected to the ground, and the other end
of the filter resistor is connected to one end of the protection
capacitor.
20. A thermal runaway detection method for the thermal runaway
detection circuit of claim 1, wherein the thermal runaway detection
method comprises: obtaining, by the processing module, thermal
runaway detection data; and determining, by the processing module,
whether thermal runaway occurs in the battery pack based on the
thermal runaway detection data, wherein the thermal runaway
detection data includes battery pack data and sampled data
collected from sampling points, and the sampling points are
disposed between the two connected voltage dividing resistor sets.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application is based upon and claims the
benefits of Chinese Patent Application No. 201910362174.5 filed on
Apr. 30, 2019, the entire contents of which are incorporated herein
by reference.
FIELD
[0002] The present disclosure generally relates to batteries, and
particularly to a thermal runaway detection circuit and method.
BACKGROUND
[0003] With rapid development of new energy sources, new energy
sources can provide power for more and more devices. For example, a
battery pack can be used as power sources to power new energy
vehicles, new energy ships, new energy aircraft, and so on. The
battery pack may generate heat during operation. Under normal
conditions, the heat generated by the battery packs is
controllable. However, under abnormal conditions, such as collision
and overcharge, etc., the heat generated by the battery pack is
uncontrollable, resulting in thermal runaway. In the event of
thermal runaway, a fire may be caused, which may threaten safety of
the battery pack, the devices in which the battery pack is
installed, and personal safety of the person concerned.
[0004] In order to improve the safety of the battery pack, a
battery management system (BMS) is currently used to monitor change
of voltage or temperature to determine whether thermal runaway
occurs. However, in the event of thermal runaway, a circuit board
or monitoring unit used to communicate with the BMS may be
sputtered and burned by the high-temperature electrolyte generated
from the thermal runaway. Therefore, the BMS cannot detect thermal
runaway, and the safety of the battery pack is reduced.
SUMMARY
[0005] The present disclosure provides a thermal runaway detection
circuit and method.
[0006] In a first aspect, the present disclosure provides a thermal
runaway detection circuit. The thermal runaway detection circuit
may include: a sensing module including a sensing cable, wherein a
distance between at least a portion of the sensing cable and a cell
of a battery pack is less than a temperature sensitive distance
threshold; a detection module connected to the sensing cable and
including at least one set of voltage dividing resistors, wherein
one end of each set of voltage dividing resistors is connected to a
first power supply terminal, and the other end of each set of
voltage dividing resistors is connected to the ground, and each set
of voltage dividing resistors includes at least two voltage
dividing resistor sets connected in series; a processing module
connected to the detection module, wherein the processing module is
configured to obtain thermal runaway detection data, and determine
whether thermal runaway occurs in the battery pack based on the
thermal runaway detection data, wherein the thermal runaway
detection data includes battery pack data and sampled data
collected from sampling points, and the sampling points are
disposed between the two connected voltage dividing resistor
sets.
[0007] In a second aspect, the present disclosure provides a
thermal runaway detection method for the thermal runaway detection
circuit of the first aspect. The method may include: obtaining, by
the processing module, thermal runaway detection data; and
determining, by the processing module, whether thermal runaway
occurs in the battery pack based on the thermal runaway detection
data; wherein the thermal runaway detection data includes battery
pack data and sampled data collected from sampling points, the
sampling points are disposed between the two connected voltage
dividing resistor sets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present disclosure can be better understood by reading
the following detailed description with reference to the attached
drawings, where the same or similar numerals represent the same or
similar features.
[0009] FIG. 1 is a schematic structural diagram of a thermal
runaway detection circuit according to an embodiment of the present
disclosure;
[0010] FIG. 2 is a schematic structural diagram of a thermal
runaway detection circuit according to another embodiment of the
present disclosure;
[0011] FIG. 3 is a schematic structural diagram of a thermal
runaway detection circuit according to still another embodiment of
the present disclosure;
[0012] FIG. 4 is a schematic structural diagram of a thermal
runaway detection circuit according to yet another embodiment of
the present disclosure;
[0013] FIG. 5 is a flowchart of a thermal runaway detection method
according to an embodiment of the present disclosure;
[0014] FIG. 6 is a flowchart of a thermal runaway detection method
according to another embodiment of the present disclosure;
[0015] FIG. 7 is a flowchart of a thermal runaway detection method
according to still another embodiment of the present
disclosure.
DETAILED DESCRIPTION
[0016] Features of various aspects and exemplary embodiments of the
present disclosure will be described in detail below. In the
following detailed description, many specific details are disclosed
to provide a thorough understanding of the present disclosure.
However, it is apparent to a person skilled in the art that the
present disclosure may be practiced without some of these specific
details. The following descriptions of embodiments are merely to
provide a better understanding of the present disclosure through
illustrating examples of the present disclosure. The present
disclosure is by no means limited to any specific configuration and
algorithm disclosed below, but rather covering any modification,
substitution, and improvement of elements, components, and
algorithms without departing from the spirit of the present
disclosure. In the appended drawings and the following
descriptions, well-known structures and techniques are not
illustrated to avoid unnecessarily obscuring the present
disclosure.
[0017] Embodiments of the present disclosure provide a thermal
runaway detection circuit and method, which may be used in a
scenario for monitoring a thermal runaway of a battery pack. The
battery pack may include at least one cell. The battery pack may be
a battery module, a battery package, or the like, which is not
limited herein. In the embodiments of the disclosure, the thermal
runaway detection circuit may detect the thermal runaway of the
battery pack in time and facilitate corresponding measures in the
subsequent process, so as to improve the safety of the battery
pack.
[0018] FIG. 1 is a schematic structure diagram of a thermal runaway
detection circuit according to an embodiment of the present
disclosure. As shown, the thermal runaway detection circuit may
include a sensing module P1, a detection module P2, and a
processing module P3.
[0019] The sensing module P1 includes a sensing cable. The distance
between at least a portion of the sensing cable and a cell of the
battery pack is less than a temperature sensitive distance
threshold. The number and type of sensing cables may be set
according to specific operation scenarios and operation
requirements, which is not limited herein.
[0020] The temperature sensitive distance threshold is a distance
threshold with which the sensing cable is able to sensitively sense
that the temperature of a cell in the battery pack is above a
temperature threshold. When the distance between the sensing cable
and the cell in the battery pack is less than the temperature
sensitive distance threshold, the error between the temperature
corresponding to the on-off state of the sensing cable being caused
to change and the actual temperature of the cell in the battery
pack is within an acceptable range. The temperature sensitive
distance threshold may be set according to a characteristic
parameter of the sensing cable and a characteristic parameter of
the cell in combination with the specific operation scenarios and
operation requirements, which is not limited herein.
[0021] In some examples, when the temperature of the cell is higher
than high-temperature temperature threshold, the on-off state of at
least a portion of the sensing cable whose distance from the cell
is less than the temperature sensitive distance threshold may
change, for example, the sensing cable may be open circuited.
[0022] In some examples, in order to be able to detect thermal
runaway of the battery pack more timely, at least a portion of the
sensing cable may be disposed right above a cell explosion-proof
valve port of the cell of the battery pack. When thermal runaway
occurs in the battery pack, the cell explosion-proof valve port
will rupture, and high-temperature electrolyte, high-temperature
gas, etc. will be ejected from the explosion-proof valve port of
the cell. At least a portion of the sensing cable being disposed
right above the cell explosion-proof valve port of the cell of the
battery pack may make the sensing cable more sensitive to thermal
runaway sensing of the battery pack. As a result, accuracy and
timeliness in thermal runaway detection may be further
improved.
[0023] The detection module P2 is connected to the sensing cable.
The detection module P2 includes at least one set of voltage
dividing resistors. One end of each set of voltage dividing
resistors is connected to a first power supply terminal, and the
other end of each set of voltage dividing resistors is connected to
the ground. Each set of voltage dividing resistors includes at
least two voltage dividing resistors in series.
[0024] The first power supply terminal may supply a voltage, for
example, a voltage of 5V. If the battery pack and the thermal
runaway detection circuit are installed in a power vehicle, the
voltage of 5V of the first power supply terminal may be provided by
the lead-acid battery in the power vehicle.
[0025] A set of voltage dividing resistors includes at least one
resistor. If a set of voltage dividing resistors includes a
plurality of resistors, the number of resistors and the connection
relationship therebetween are not limited herein. The set of
voltage dividing resistors is used for voltage division so that the
processing module P3 may collect sampled data from sampling points
disposed between two connected sets of voltage dividing
resistors.
[0026] In some examples, the detection module P2 may be
specifically disposed in a Battery Management Unit (BMU). The BMU
may include a housing structure. The detection module P2 may be
protected from the high-temperature electrolyte generated from
thermal runaway of the battery pack. Alternatively, the position of
the detection module P2 is not specifically limited, and the
detection module P2 may be provided with a protective cover to
protect the detection module P2 from the high-temperature
electrolyte generated from thermal runaway of the battery pack, so
as to further ensure the timeliness of the detection of the thermal
runaway and the safety of the thermal runaway detection
circuit.
[0027] The processing module P3 may be connected to the detection
module P2. The processing module P3 may be configured to obtain
thermal runaway detection data, and determine whether thermal
runaway occurs in the battery pack based on the thermal runaway
detection data.
[0028] The thermal runaway detection data may include battery-pack
data and sampled data collected from sampling points which may be
disposed between the two connected sets of voltage dividing
resistors.
[0029] The battery-pack data is data related to the battery pack,
which may characterize various states of the battery pack, such as
temperature, voltage, faults, and effectiveness of external
communications.
[0030] The processing module P3 collects sampled data from the
sampling points. Specifically, the sampling port may be disposed at
the sampling point. The position and number of sampling points can
be set according to specific operation scenarios and operation
requirements, which are not limited herein. The sampled data may
include electrical parameter signals such as voltage, current,
etc., which are not limited herein.
[0031] According to the sampled data collected from the sampling
point, the on-off state of the sensing cable may be determined,
that is, the open-circuit or normal path of the sensing cable may
be determined. According to the sampled data in combines with the
battery pack data, the processing module P3 determine whether
thermal runaway occurs in the battery pack to ensure reliability in
thermal runaway detection.
[0032] In some examples, the processing module P3 may be disposed
in the BMU, or functions of the processing module P3 may be
integrated into the BMU. For example, the processing module P3 may
specifically be a micro control unit (MCU) in the BMU, which is not
limited herein.
[0033] In an embodiment of the present disclosure, the thermal
runaway detection circuit may include the sensing module P1, the
detection module P2, and the processing module P3. The sensing
module may include a sensing cable, and the distance between at
least a portion of the sensing cable and the cell in the battery
pack is less than the temperature sensitive distance threshold,
such that the state of the sensing cable can be affected by the
temperature of the cell in the battery pack. When the sensing cable
is affected by the temperature after the thermal runaway of the
cell, for example, the high temperature of jet electrolyte after
the thermal runaway of the cell, the on-off state of the sensing
cable will change, so that the sampled data collected from the
sampling points will change. The processing module P3 may detect
the thermal runaway in the battery pack in time based on the
thermal runaway detection data. As a result, the safety of the
battery pack can be improved.
[0034] In some examples, the processing module P3 in the above
embodiments may be further configured to send an alarm signal to a
vehicle controller to trigger the vehicle controller to take
measures or remind the person concerned if it is determined that
thermal runaway occurs in the battery pack.
[0035] In embodiments of the present disclosure, if the thermal
runaway detection circuit is installed in the power vehicle, the
thermal runaway detection and alarm can still be performed while
the whole vehicle of the power vehicle is in the stopped state.
[0036] The following describes the specific structure of the
thermal runaway detection circuit.
[0037] FIG. 2 is a schematic structure diagram of a thermal runaway
detection circuit according to another embodiment of the present
disclosure (the processing module P3 is not shown). As shown in
FIG. 2, the sensing cable in the detection module P2 may include a
first sensing cable and a second sensing cable. The detection
module P2 may include two sets of voltage dividing resistors.
[0038] The first sensing cable and the second sensing cable may be
specifically disposed on a circuit board above the battery pack.
The number of circuit boards is not limited. For example, the
circuit board may specifically be a flexible printed circuit (FPC),
and the first sensing cable and the second sensing cable may be
copper wires coated in the FPC substrate, which is different from
the sampling cable originally set on the FPC to collect
temperature, voltage, etc. The first sensing cable and the second
sensing cable are thinner than the sampling cable, that is, a
diameter of the first sensing cable and a diameter of the second
sensing cable are smaller than a diameter of the sampling
cable.
[0039] At least a portion of the first sensing cable and at least a
portion of the second sensing cable are located right above the
cell explosion-proof valve port of the cell of the battery pack.
When thermal runaway occurs in the battery pack, the cell
explosion-proof valve will rupture, and high-temperature
electrolyte, high-temperature gas, etc. will be ejected from the
explosion-proof valve port of the cell. At least a portion of the
first sensing cable and at least a portion of the second sensing
cable being disposed right above the cell explosion-proof valve
port of the cell of the battery pack, may make the first sensing
cable and the second sensing cable more sensitive to thermal
runaway sensing of the battery pack. As a result, accuracy and
timeliness in thermal runaway detection may be further
improved.
[0040] Further, the first sensing cable and the second sensing
cable may pass right above the explosion-proof valve port of all
the cells of the battery pack. The specific arrangement of the
first sensing cable and the second sensing cable may also be
determined in combination with the internal structure of the
battery pack. For example, the battery pack is a battery set, the
battery set includes a plurality of battery units, and a plurality
of circuit boards may be disposed in the battery pack. The first
sensing cable may include a plurality of sensing cable segments,
each sensing cable segment being disposed on one circuit board, and
each sensing cable segment may be connected by other wiring
harnesses or connectors or the like. The arrangement of the second
sensing cable may be referred to the first sensing cable, and
details are not repeated herein again.
[0041] In the embodiments of the present disclosure, the sampling
point includes a first sampling point, a second sampling point, a
third sampling point, and a fourth sampling point.
[0042] The first set of voltage dividing resistors includes a first
voltage dividing resistor set, a second voltage dividing resistor
set, and a third voltage dividing resistor set in series. One end
of the first voltage dividing resistor set is connected to the
first power supply terminal. One end of the third voltage dividing
resistor set is connected to the ground.
[0043] For example, as shown in FIG. 2, the first voltage dividing
resistor set includes a resistor R1, the second voltage dividing
resistor set includes a resistor R2, and the third voltage dividing
resistor set includes a resistor R3. One end of the resistor R1 is
connected to the first power supply terminal V1, and the other end
of the resistor R1 is connected to one end of the resistor R2. The
other end of the resistor R2 is connected to the other end of the
resistor R3. One end of the resistor R3 is connected to the
ground.
[0044] The first sampling point is disposed between the first
voltage dividing resistor set and the second voltage dividing
resistor set. The second sampling point is disposed between the
second voltage dividing resistor set and the third voltage dividing
resistor set. One end of the first sensing cable is connected to
the first sampling point, and the other end of the first sensing
cable is connected to the second sampling point.
[0045] For example, as shown in FIG. 2, the first sampling point is
labeled as AD1 and the second sampling point is labeled as AD2. The
first sampling point AD1 is disposed between the resistor R1 and
the resistor R2, and the second sampling point AD2 is disposed
between the resistor R2 and the resistor R3. The first sensing
cable is labeled with a, and the first sensing cable a is
equivalent to being connected in parallel with the resistor R2.
[0046] The second set of voltage dividing resistors includes a
fourth voltage dividing resistor set, a fifth voltage dividing
resistor set, and a sixth voltage dividing resistor set in series.
One end of the fourth voltage dividing resistor set is connected to
the first power supply terminal. One end of the sixth voltage
dividing resistor set is connected to the ground.
[0047] For example, as shown in FIG. 2, the fourth voltage dividing
resistor set includes a resistor R4, the fifth voltage dividing
resistor set includes a resistor R5, and the sixth voltage dividing
resistor set includes a resistor R6. One end of the resistor R4 is
connected to the first power supply terminal V1, and the other end
of the resistor R4 is connected to one end of the resistor R5. The
other end of the resistor R5 is connected to the other end of the
resistor R6. One end of the resistor R6 is connected to the
ground.
[0048] The third sampling point is disposed between the fourth
voltage dividing resistor set and the fifth voltage dividing
resistor set. The fourth sampling point is disposed between the
fifth voltage dividing resistor set and the sixth voltage dividing
resistor set. One end of the second sensing cable is connected to
the third sampling point, and the other end of the second sensing
cable is connected to the fourth sampling point.
[0049] For example, as shown in FIG. 2, the third sampling point is
labeled as AD3 and the fourth sampling point is labeled as AD4. The
third sampling point AD3 is disposed between the resistor R4 and
the resistor R5, and the fourth sampling point AD4 is disposed
between the resistor R5 and the resistor R6. The second sensing
cable is labeled with b, and the second sensing cable b is
equivalent to being connected in parallel with the resistor R5.
[0050] If the first sensing cable a is not open circuited, the
circuit from the first power supply terminal V1 to the ground
through the first set of voltage dividing resistors is: the first
power supply terminal V1.fwdarw.the resistor R1.fwdarw.the first
sensing cable a.fwdarw.the resistor R3.fwdarw.ground.
[0051] If the first sensing cable a is open circuited, the circuit
for the first power supply terminal V1 to the ground through the
first set of voltage dividing resistors is: the first power supply
terminal V1.fwdarw.the resistor R1.fwdarw.the resistor
R2.fwdarw.the resistor R3.fwdarw.ground.
[0052] Similarly, if the second sensing cable b is not open
circuited, the circuit from the first power supply terminal V1 to
the ground through the second set of voltage dividing resistors is:
the first power supply terminal V1.fwdarw.the resistor
R4.fwdarw.the second sensing cable b.fwdarw.the resistor
R6.fwdarw.ground.
[0053] If the second sensing cable b is open circuited, the circuit
from the first power supply terminal V1 to the ground through the
second set of voltage dividing resistors is: the first power supply
terminal V1.fwdarw.the resistor R4.fwdarw.the resistor
R5.fwdarw.the resistor R6.fwdarw.ground.
[0054] Therefore, when the first sensing cable a is open circuited
or not open circuited, the first sampled data collected from the
first sampling point AD1 and the second sampled data collected from
the second sampling point AD2 are different, and an on-off state of
the first sensing cable a may be determined based on the first
sampled data and the second sampled data. The on-off state includes
an open circuit and a non-open circuit (i.e., a normal path).
[0055] Similarly, when the second sensing cable b is open circuited
or not open circuited, the third sampled data collected from the
third sampling point AD3 and the fourth sampled data collected from
the fourth sampling point AD4 are different, and an on-off state of
the second sensing cable b may be determined based on the third
sampled data and the fourth sampled data determine. The on-off
state includes an open circuit and non-open circuit (i.e., a normal
path).
[0056] The processing module P3 may be configured to: obtain a
first sampled data, a second sampled data, a third sampled data,
and a fourth sampled data from the first sampling point, the second
sampling point, the third sampling point, and the fourth sampling
point respectively; determine an on-off state of the first sensing
cable based on the first sampled data and the second sampled data;
determine an on-off state of the second sensing cable based on the
third sampled data and the fourth sampled data; and determine
whether thermal runaway occurs in the battery pack based on the
on-off state of the first sensing cable and the on-off state of the
second sensing cable.
[0057] In some examples, a first open-circuit threshold range and a
second open-circuit threshold range for determining that the first
sensing cable is open circuited, and a third open-circuit threshold
range and a fourth open-circuit threshold range for determining
that the second sensing cable is open circuited may be preset.
[0058] In some examples, a first normal path threshold range and a
second normal path threshold range for determining the first
sensing cable is a normal path, and a third normal path threshold
range and a fourth normal path for determining the second sensing
cable is a normal path may also be preset.
[0059] The first open-circuit threshold range and the second
open-circuit threshold range are related to a voltage provided by
the first power supply terminal, a first voltage dividing resistor
set, a second voltage dividing resistor set, a third voltage
dividing resistor set, and an acceptable error range. That is to
say, the first open-circuit threshold range and the second-open
circuit threshold range may be calculated based on the voltage
provided by the first power supply terminal, the first voltage
dividing resistor set, the second voltage dividing resistor set,
the third voltage dividing resistor set, and the acceptable error
range.
[0060] The third open-circuit threshold range and the fourth
open-circuit threshold range are related to a voltage provided by
the first power supply terminal, a fourth voltage dividing resistor
set, a fifth voltage dividing resistor set, a sixth voltage
dividing resistor set, and an acceptable error range. That is to
say, the third open-circuit threshold range and the fourth
open-circuit may be calculated based on the voltage supplied by the
first power supply terminal, the fourth voltage dividing resistor
set, the fifth voltage dividing resistor set, the sixth voltage
dividing resistor set, and the acceptable error range.
[0061] The first path threshold range and the second path threshold
range are related to a voltage provided by the first power supply
terminal, a first voltage dividing resistor set, a third voltage
dividing resistor set, and an acceptable error range. That is to
say, the first path threshold range and the second path threshold
range may be calculated based on the voltage provided by the first
power supply terminal, the first voltage dividing resistor set, the
third voltage dividing resistor set, and the acceptable error
range.
[0062] The third path threshold range and the fourth path threshold
range are related to a voltage provided by the first power supply
terminal, a fourth voltage dividing resistor set, a sixth voltage
dividing resistor set, and an acceptable error range. That is to
say, the third path threshold range and the fourth path threshold
range may be calculated based on the voltage provided by the first
power supply terminal, the fourth voltage dividing resistor set,
the sixth voltage dividing resistor set, and the acceptable error
range.
[0063] It should be noted that the first path threshold range may
be the same as the second path threshold range may be the same, or
the deviation between the first path threshold range and the second
path threshold range is within an acceptable range. The third path
threshold range may be the same as the fourth path threshold range,
or the deviation between the third path threshold range and the
fourth path threshold range is within an acceptable range.
[0064] The processing module P3 may be configured to: determine
that the first sensing cable is open circuited when the first
sampled data is in the first open-circuit threshold range, and the
second sampled data is in the second open-circuit threshold range;
determine that the second sensing cable is open circuited when the
third sampled data is within the third open-circuit threshold
range, and the fourth sampled data is within the fourth
open-circuit threshold range; and determine thermal runaway occurs
in the battery pack when the first sensing cable and the second
sensing cable are both open circuited, and at least one parameter
of the battery pack data satisfies the fault condition within the
preset period.
[0065] The battery pack data includes at least one parameter.
Parameters can be used to characterize various states of the
battery pack, such as temperature, voltage, faults, and
effectiveness of external communications.
[0066] In some examples, the battery pack data may specifically be
various types of battery related parameters, for example, one or
more parameters of the maximum temperature of a cell in a battery
pack, the temperature change rate of a cell in the battery pack,
the difference between the maximum temperature of a cell in the
battery pack and the minimum temperature of a cell in the battery
pack, the minimum voltage of a cell in the battery pack, the number
of voltage sampling open-circuit faults of the battery pack, the
temperature sensing failure parameter, and the cell monitoring
communication failure parameter, which are not limited herein.
[0067] The fault condition may include a parameter exceeding the
safety parameter threshold range or a parameter characterizing a
failure. The fault conditions may be set according to specific
operation scenarios and operation requirements, which is not
limited herein. Setting of the preset period can effectively avoid
at least a part misjudgment for the thermal runaway and improve the
reliability of the thermal runaway detection.
[0068] Corresponding to each parameter in the battery pack data,
there are different safety parameter threshold ranges. The safety
parameter threshold range corresponding to the maximum temperature
of a cell in the battery pack may specifically be a maximum
temperature safety threshold range. The safety parameter threshold
range corresponding to the temperature change rate of a cell in the
battery pack may specifically be a temperature change rate safety
threshold range. The safety parameter threshold range corresponding
to the difference between the maximum temperature and the minimum
temperature of a cell in the battery pack may specifically be a
temperature difference safety threshold range. The safety parameter
threshold range corresponding to the minimum voltage of a cell in
the battery pack may specifically be a minimum voltage safety
threshold range. The safety parameter threshold range corresponding
to the number of voltage sampling open-circuit faults of the
battery pack may specifically be a fault data safety threshold
range.
[0069] The temperature sensing failure parameter may characterize
whether the sensor or sensing component used for temperature
sensing fails. For example, a negative temperature coefficient
(NTC) thermistor may be provided in the battery pack, and the
temperature sensing failure parameter may indicate whether the NTC
thermistor disposed in the battery pack fails completely.
[0070] The cell monitoring communication failure parameter may
characterize whether a communication between the component that
monitors the cell and the BMU fails (i.e., whether the
communication is lost). For example, the cell of the battery pack
may be equipped with a Cell Supervision Circuit (CSC), and the cell
monitoring communication failure parameter may indicate whether the
communication between the CSC and the BMU fails.
[0071] For example, following several examples of determination of
the thermal runaway of the battery pack are provided in the case of
determining that the first sensing cable and the second sensing
cable are open circuited. However, it should be noted that the
determination of the thermal runaway of the battery pack may
include, but is not limited to, the following examples.
[0072] Example 1: if it is determined that the first sensing cable
and the second sensing cable are open circuited within 10 minutes,
and the maximum temperature of a cell in the battery pack is
greater than 68.4.degree. C. for 2 seconds, it can be determined
that thermal runaway occurs in the battery pack.
[0073] Example 2: if it is determined that the first sensing cable
and the second sensing cable are open circuited within 10 minutes,
and the temperature change rate of a cell in the battery pack is
greater than 3.degree. C./second for 2 seconds, it can be
determined that thermal runaway occurs in the battery pack.
[0074] Example 3: if it is determined that the first sensing cable
and the second sensing cable are open circuited within 10 minutes,
and the difference between the maximum temperature and the minimum
temperature of a cell in the battery pack is greater than
30.degree. C., it can be determined that thermal runaway occurs in
the battery pack.
[0075] Example 4: if it is determined that the first sensing cable
and the second sensing cable are open circuited within 10 minutes,
and the minimum voltage of a cell in the battery is less than 2V
for 300 milliseconds, it can be determined that thermal runaway
occurs in the battery pack.
[0076] Example 5: if it is determined that the first sensing cable
and the second sensing cable are open circuited within 10 minutes,
and the number of voltage sampling open-circuit faults of the
battery pack is greater than or equal to 1, it can be determined
that thermal runaway occurs in the battery pack.
[0077] Example 6: if it is determined that the first sensing cable
and the second sensing cable are open circuited within 10 minutes,
and the temperature sensing failure parameter may indicate that the
NTC thermistor disposed in the battery pack fails completely, it
can be determined that thermal runaway occurs in the battery
pack.
[0078] Example 7: if it is determined that the first sensing cable
and the second sensing cable are open circuited within 10 minutes,
and the cell monitoring communication failure parameter may
characterize that the communication between the CSC and the BMU
fails, it can be determined that thermal runaway occurs in the
battery pack.
[0079] In other examples, the processing module P3 may be
configured to: determine thermal runaway occurs in the battery pack
when it is determined that at least one sensing cable of the first
sensing cable and the second sensing cable is not open circuited,
and at least one set of parameters in the battery pack data
satisfies the fault condition within a preset period.
[0080] It is determined that at least one sensing cable of the
first sensing cable and the second sensing cable is open circuited,
specifically, only one of the first sensing cable and the second
sensing cable is open circuited, or specifically, the first sensing
cable and the second sensing cable are both not open circuited.
[0081] A set of parameters includes at least two parameters. A set
of parameters includes, but is not limited to, any of the following
sets of parameters:
[0082] The first set: the minimum voltage of a cell in the battery
pack, and the maximum temperature of a cell in the battery
pack.
[0083] The second set: the minimum voltage of a cell in the battery
pack, and the temperature change rate of a cell in the battery
pack.
[0084] The third set: the minimum voltage of a cell in the battery
pack, and the temperature change rate of a cell in the battery
pack.
[0085] The fourth set: the temperature change rate of a cell in the
battery pack, and the maximum temperature of a cell in the battery
pack.
[0086] The fifth set: the temperature change rate of a cell in the
battery pack, and the difference between the maximum temperature of
a cell in the battery pack and the minimum temperature of a cell in
the battery pack.
[0087] The sixth set: the number of voltage sampling open-circuit
faults of the battery pack, and the maximum temperature of a cell
in the battery pack.
[0088] The seventh set: the number of voltage sampling open-circuit
faults of the battery pack, and the temperature change rate of a
cell in the battery pack.
[0089] The eighth set: the number of voltage sampling open-circuit
faults of the battery pack, and the difference between the maximum
temperature of a cell in the battery pack and the minimum
temperature of a cell in the battery pack.
[0090] The ninth set: the number of voltage sampling open-circuit
faults of the battery pack, and the temperature sensing failure
parameter.
[0091] The specific parameters in each of the above parameters and
related content may be referred to the related descriptions in the
above embodiments, and details are not described herein again. The
fault condition may include a parameter exceeding the safety
parameter threshold range or a parameter characterizing a
failure.
[0092] For example, as an example, a plurality sets of parameters
and their corresponding fault conditions are listed below. If at
least one set of parameters meets its corresponding fault
condition, it can be determined that thermal runaway occurs in the
battery pack. At least two parameters satisfying its corresponding
fault condition may further improve the reliability of the thermal
runaway detection. It should be noted that the parameters and fault
conditions in the embodiments of the present disclosure may
include, but be not limited to, the following parameters and fault
conditions.
[0093] The first set of parameters and corresponding fault
conditions: the minimum voltage of a cell in the battery pack is
less than 2V for 300 milliseconds, and the maximum temperature of a
cell in the battery pack is greater than 68.degree. C. for 2
seconds.
[0094] The second set of parameters and corresponding fault
conditions: the minimum voltage of a cell in the battery pack is
less than 2V for 300 milliseconds, and the temperature change rate
of a cell in the battery pack is greater than 3.degree. C./second
for 2 seconds.
[0095] The third set of parameters and corresponding fault
conditions: the minimum voltage of a cell in the battery pack is
less than 2V for 300 milliseconds, and the difference between the
maximum temperature and the minimum temperature of a cell in the
battery pack is greater than 30.degree. C.
[0096] The fourth set of parameters and corresponding fault
conditions: the temperature change rate of a cell in the battery
pack is greater than 3.degree. C./second for 2 seconds, and the
maximum temperature of a cell in the battery pack is greater than
68.degree. C. for 2 seconds.
[0097] The fifth set of parameters and corresponding fault
conditions: the temperature change rate of a cell in the battery
pack is greater than 3.degree. C./second for 2 seconds, and the
difference between the maximum temperature and the minimum
temperature of a cell in the battery pack is greater than
30.degree. C.
[0098] The sixth set of parameters and corresponding fault
conditions: the number of voltage sampling open-circuit faults of
the battery pack is greater than or equal to 1, and the maximum
temperature of a cell in the battery pack is greater than
68.degree. C. for 2 seconds.
[0099] The seventh set of parameters and corresponding fault
conditions: the number of voltage sampling open-circuit faults of
the battery pack is greater than or equal to 1, and the temperature
change rate of a cell in the battery pack is greater than 3.degree.
C./second for 2 seconds.
[0100] The eighth set of parameters and corresponding fault
conditions: the number of voltage sampling open-circuit faults of
the battery pack is greater than or equal to 1, and the difference
between the maximum temperature and the minimum temperature of a
cell in the battery pack is greater than 30.degree. C.
[0101] The ninth set of parameters and corresponding fault
conditions: the number of voltage sampling open-circuit faults of
the battery pack is greater than or equal to 1, and the temperature
sensing failure parameter characterizes that the NTC thermistor
disposed in the battery pack completely fails.
[0102] If at least one set of the above nine sets of parameters
satisfies corresponding fault conditions, it may be determined that
thermal runaway occurs in the battery pack.
[0103] In still another example, if it is determined that only one
of the first sensing cable and the second sensing cable is open
circuited, it may be determined that there is not a fault at the
battery pack, and no fault handling is performed.
[0104] It should be noted that if the first sampled data is neither
within the first open-circuit threshold range nor within the first
path threshold range, it may be determined that there is a fault at
the sampling port of the first sampling point. If the second
sampled data is neither within the second open-circuit threshold
range nor within the second path threshold range, it may be
determined that there is a fault at the sampling port of the second
sampling point. If the third sampled data is neither within the
third open-circuit threshold range nor within the third path
threshold range, it may be determined that there is a fault at the
sampling port of the third sampling point. If the fourth sampled
data is neither within the fourth open-circuit threshold range nor
within the fourth path threshold range, it may be determined that
there is a fault at the sampling port of the fourth sampling
point.
[0105] If it is determined that there is a fault at the sampling
port of the sampling point, a prompt message about sampling fault
may be sent to prompt the vehicle controller to take corresponding
measures or prompt the persons related.
[0106] In some examples, the processing module P3 is further
configured to: send a thermal runaway warning message when it is
determined that at least one of the first sensing cable and the
second sensing cable is not open circuited and the battery pack
data satisfies the fault condition.
[0107] The battery pack data includes the maximum voltage of a cell
in the battery pack during charging, the actual state of charge of
the battery pack during charging, and the charging current of the
battery pack during charging. Fault conditions include a parameter
that exceed the safety parameter threshold range.
[0108] Corresponding to the specific parameters of the battery pack
data, the safety parameter threshold range includes a voltage
safety parameter threshold range, a state of charge safety
parameter threshold range, and a current safety parameter threshold
range.
[0109] That is to say, if it is determined that at least one of the
first sensing cable and the second sensing cable is not open
circuited, the maximum voltage of a cell in the battery pack during
charging exceeds a voltage safety parameter threshold range, the
actual state of charge of the battery pack during charging exceeds
a state of charge safety parameter threshold range, and the
charging current of the battery pack during charging exceeds a
current safety parameter threshold range, it may be predicted that
thermal runaway is about to occur in the battery pack. The thermal
runaway warning message may be sent, so that corresponding measures
can be taken in advance to avoid thermal runaway and further
improve the safety of the battery pack.
[0110] For example, during the charging, if the maximum voltage of
a cell in the battery pack is greater than 1.1 times the tertiary
overvoltage threshold, the actual state of charge of the battery
pack is greater than 115%, and the charging current is greater than
or equal to 0.33 times the rated charge current under
one-hour-rate, it may be predicted that thermal runaway is about to
occur in the battery pack. Then the thermal runaway warning message
may be sent.
[0111] In some embodiments, the state of the BMU includes an
operating state and a sleep state. When the BMU is in the operating
state, the power module P5 of the BMU controls the power supply
module of the BMU to power on, so that the BMU is in the operating
state, can perform data monitoring on the battery pack normally,
such as voltage monitoring, current monitoring, temperature
monitoring, insulation monitoring, and state of charge monitoring,
etc., and can obtain voltage, current, temperature, state of
charge, etc. as thermal runaway detection data. When the BMU is in
the sleep state, the power module of the BMU controls the power
module of the BMU to power off. The BMU stops monitoring the
battery pack the data. The power module P5 can be implemented as a
power chip, such as a system base chip (SBC), which is not limited
herein.
[0112] If thermal runaway occurs in the battery pack in the process
of the BMU being in the sleep state, the BMU stops data monitoring
and cannot provide thermal runaway detection data. If a function of
the processing module P3 is integrated in the BMU and the BMU is in
the sleep state, detection and determination of thermal runaway
cannot be carried out.
[0113] In the process of the BMU being in a sleep state, the
thermal runaway detection may also be performed, and the thermal
runaway detection data may be obtained in the thermal runaway
detection process. FIG. 3 is a schematic structural diagram of a
thermal runaway detection circuit according to still another
embodiment of the present disclosure (processing module P3 is not
shown). The sleep-wakeup module P4 shown in FIG. 2 and FIG. 3 can
wake up the BMU, when thermal runaway may occurs, and thermal
runaway detection is required for the BMU being in the sleep state.
The difference between FIG. 3 and FIG. 2 is that the detection
module P2 in the thermal runaway detection circuit shown in FIG. 3
may further include some protection devices and/or filter
components. The protection device may specifically include a
protection capacitor, and the filter component may specifically
include a filter capacitor and a filter resistor.
[0114] The sleep-wakeup module P4 is disposed between the first
power supply terminal and all of voltage dividing resistor sets,
and the sleep-wakeup module P4 is configured to send a control
signal to the power module P5 of the battery management unit when
the battery management unit is in the sleep state.
[0115] The control signal is used to instruct the power module P5
to control the battery management unit to remain in a sleep state
or switch to an operating state. For example, if the voltage of the
control signal is higher than or equal to the threshold voltage of
the power module P5, that is, the control signal controls the BMU
to switch to the operating state, the BMU is woken up. If the
voltage of the control signal is lower than the startup voltage
threshold of the power module P5, that is, the control signal
controls the BMU to remain in the sleep state, the BMU is not woken
up.
[0116] In some examples, the sleep-wakeup module P4 includes a
ninth voltage dividing resistor set. Alternatively, the
sleep-wakeup module P4 includes a ninth voltage dividing resistor
set and a diode. The diode is disposed between the ninth voltage
dividing resistor set and the power module P5. Specifically, the
anode of the diode is connected to the ninth voltage dividing
resistor set, and the cathode of the diode is connected to the
power module P5.
[0117] For example, as shown in FIG. 3, the sleep-wakeup module P4
includes a ninth voltage dividing resistor set and a diode. The
ninth voltage dividing resistor set includes a resistor R9. One end
of the resistor R9 is connected to the first power supply terminal
V1, and the other end of the resistor R9 is connected to the anode
of the diode D1. The cathode of the diode D1 is connected to the
power module P5, one end of the resistor R1, and one end of the
resistor R4.
[0118] It should be noted that if the BMU is in the operating
state, the second power supply terminal continuously provides an
operating signal to the power module P5 of the BMU. The second
power supply is powered up when the BMU is in operation state,
thereby ensuring continuously providing the operating signal to the
BMU. The second power supply is powered off when the BMU is in the
sleep state, and the sleep-wakeup module P4 wakes up the BMU. As
shown in FIG. 3, a resistor R10 may be disposed between the second
power supply terminal V2 and the power module P5 of the BMU. A
diode D2 may also be disposed between the resistor R10 and the
power module P5. The anode of the diode D2 is connected to the
resistor R10, and the cathode of the diode D2 is connected to the
power module P5. Both the diode D1 and the diode D2 may prevent
current from flowing back, and the diode D1 and the diode D2 also
have a function of competing power supply. For example, if the
voltage supplied by the second power supply terminal V2 is higher
than the voltage provided by the first power supply terminal V1,
the second power supply terminal V2 can ensure that the BMU is
continuously in the operating state when the BMU is in the
operating state.
[0119] The value of the voltage provided by the second power supply
terminal V2 and the value of the voltage supplied by the first
power supply terminal V1 may be the same or different, which are
not limited herein. For example, the voltage supplied by the second
power supply terminal V2 is 12V.
[0120] It is worth mentioning that if the thermal runaway detection
circuit includes the sleep-wakeup module P4, the sleep-wakeup
module P4 includes a ninth voltage dividing resistor set. The first
open-circuit threshold range, the second open-circuit threshold
range, the third open-circuit threshold range, the fourth
open-circuit threshold range, the first path threshold range, the
second path threshold range, the third path threshold range, and
the fourth path threshold range in the above embodiments may also
be related to the ninth voltage dividing resistor set. If the
sleep-wakeup module P4 further includes a diode, the first
open-circuit threshold range, the second open-circuit threshold
range, the third open-circuit threshold range, the fourth
open-circuit threshold range, the first path threshold range, the
second path threshold range, The third path threshold range and the
fourth path threshold range in the above embodiments are also
related to the diode.
[0121] In some examples, if the voltage provided by the second
power supply terminal is higher than the first power supply
terminal, the first open-circuit threshold range, the second
open-circuit threshold range, the third open-circuit threshold
range, the fourth open-circuit threshold range, and the first path
threshold range, the second path threshold range, the third path
threshold range, and the fourth path threshold range may also be
related to a resistor and a diode between the second power supply
terminal and the power supply module P5.
[0122] One end of the protection capacitor is connected to one end
of the voltage dividing resistor set connected to the sampling
point, and the other end of the protection capacitor is connected
to the ground. The protection capacitor prevents Electrostatic
Discharge (ESD) from occurring in the thermal runaway detection
circuit.
[0123] The sampling points include a first sampling point, a second
sampling point, a third sampling point, and a fourth sampling
point. Correspondingly, the protection capacitor may include a
first protection capacitor, a second protection capacitor, a third
protection capacitor, and a fourth protection capacitor. As shown
in FIG. 3, one end of the first protection capacitor C1 is
connected to one end of the resistor R1 connected to the first
sampling point AD1, and one end of the second protection capacitor
C2 is connected to one end of the resistor R2 and the second
sampling point AD2. One end of the protection capacitor C3 is
connected to one end of the resistor R4 connected to the third
sampling point AD3, and one end of the fourth protection capacitor
C4 is connected to one end of the resistor R5 and the fourth
sampling point AD4. The other ends of the first protection
capacitor C1, the second protection capacitor C2, the third
protection capacitor C3, and the fourth protection capacitor C4 are
connected to the ground.
[0124] The detection module P2 further includes a filter capacitor
and a filter resistor. One end of the filter capacitor is connected
to one end of the filter resistor and the sampling point, and the
other end of the filter capacitor is connected to the ground. The
other end of the filter resistor is connected to one end of the
protection capacitor.
[0125] The sampling points include a first sampling point, a second
sampling point, a third sampling point, and a fourth sampling
point. Correspondingly, the filter capacitors may include a first
filter capacitor C5, a second filter capacitor C6, a third filter
capacitor C7, and a fourth filter capacitor C8. The filter
resistors may include a resistor R11, a resistor R12, a resistor
R13, and a resistor R14. As shown in FIG. 3, one end of the first
filter capacitor C5 is connected to one end of the resistor R11,
and the other end of the first filter capacitor C5 is connected to
the ground. One end of the second filter capacitor C6 is connected
to one end of the resistor R12, and the other end of the second
filter capacitor C6 is connected to the ground. One end of the
third filter capacitor C7 is connected to one end of the resistor
R13, and the other end of the third filter capacitor C7 is
connected to the ground. One end of the fourth filter capacitor C8
is connected to one end of the resistor R13, and the other end of
the fourth filter capacitor C8 is connected to the ground. The
other end of the resistor R11 is connected to the first sampling
point AD1. The other end of the resistor R12 is connected to the
second sampling point AD2. The other end of the resistor R13 is
connected to the third sampling point AD3. The other end of the
resistor R14 is connected to the fourth sampling point AD4.
[0126] The filter capacitor and the filter resistor form an RC
filter circuit, which may filter the sampled data of the sampling
point to improve the accuracy of the sampled data collected from
the sampling point, thereby improving the accuracy of the thermal
runaway detection.
[0127] FIG. 4 is a schematic structural diagram of a thermal
runaway detection circuit according to still another embodiment of
the present disclosure (the processing module P3 is not shown). As
shown in FIG. 4, the sensing cable in the sensing module P1
includes a third sensing cable. The detection module P2 includes a
set of voltage dividing resistors.
[0128] The third sensing cable is disposed in a shield above the
battery pack. The number of shields is not limited herein. In some
examples, the third sensing cable may be a tin wire or a wire made
of other material which is electrically conductive and has a
melting point below the melting point threshold. The melting point
threshold may be set according to the specific operating scenario
and operating requirements, which is not limited herein. The shield
may be a mica board, and the third sensing cable, such as a tin
wire, may be buried in the mica board.
[0129] At least a portion of the third sensing cable is disposed
right above the cell explosion-proof valve port of a cell in the
battery pack. If thermal runaway occurs in the battery pack, the
battery explosion-proof valve will rupture, and high-temperature
electrolyte, high-temperature gas, etc. will be ejected from the
explosion-proof valve port of the battery pack. At least a part of
the third sensing cable is disposed right above the explosion-proof
valve port of the cell battery in the battery pack, which may make
the third sensing cable more sensitive to the thermal runaway
sensing of the battery pack. As a result, As a result, accuracy and
timeliness in thermal runaway detection may be further
improved.
[0130] Further, the third sensing cable may pass right above the
explosion-proof valve port of all the cells in the battery pack.
The specific arrangement of the third sensing cable may also be
determined in combination with an internal structure of the battery
pack. For example, the battery pack is a cell pack, the cell pack
includes a plurality of battery modules, and a plurality of shields
may be disposed in the battery pack. For example, the third sensing
cable may include a plurality of sensing cable segments, each of
the sensing cable segments is disposed in one of the shields, and
each of the sensing cable segments may be connected by another wire
harness or a connector or the like.
[0131] In an embodiment of the disclosure, the sampling point
includes a fifth sampling point.
[0132] The above set of voltage dividing resistor set includes a
seventh voltage dividing resistor set and an eighth voltage
dividing resistor set. The seventh voltage dividing resistor set
and the eighth voltage dividing resistor are connected in series
through the third sensing cable. One end of the seventh voltage
dividing resistor set is connected to the first power supply
terminal, and the other end of the seventh voltage dividing
resistor set is connected to the other end of the eighth voltage
dividing resistor set through the third sensing cable, and one end
of the eighth voltage dividing resistor set is connected to the
ground. The fifth sampling point is disposed between the seventh
voltage dividing resistor set and the eighth voltage dividing
resistor set.
[0133] In some embodiments, the thermal runaway detection circuit
may further include a sleep-wakeup module P4. The connection
position and role of the sleep-wakeup module P4 are substantially
the same as those of the sleep-wakeup module P4 in the above
embodiments, which may be referred to the related description in
the above embodiments, and details will not repeated herein.
[0134] For example, as shown in FIG. 4, the seventh voltage
dividing resistor set includes a resistor R7, and the eighth
voltage dividing resistor set includes a resistor R8. The ninth
voltage dividing resistor set in the sleep-wakeup module P4
includes a resistor R15. The sleep-wakeup module P4 may also
include a diode D3. One end of the resistor R15 is connected to the
first voltage terminal V1, and the other end of the resistor R15 is
connected to the anode of the diode D3. The cathode of the diode D3
is connected to one end of the resistor R7. The other end of the
resistor R7 is connected to the other end of the resistor R8
through a third sensing cable c. One end of the resistor R8 is
connected to the ground.
[0135] It should be noted that if the BMU is in the operating
state, the second power supply terminal continuously provides a
wakeup signal to the power module P5 of the BMU. The second power
supply terminal is powered up when the BMU is in operating state,
thereby ensuring that the wakeup signal is continuously provided to
the BMU. The second power supply terminal is powered off when the
BMU is in the sleep state, and the sleep-wakeup module P4 wakes up
the BMU. As shown in FIG. 4, a resistor R16 may be disposed between
the second power supply terminal V2 and the BMU. A diode D4 may
also be disposed between the resistor R16 and the power module PS.
The anode of the diode D4 is connected to the resistor R16, and the
cathode of the diode D4 is connected to the power module PS. Both
diode D3 and diode D4 prevent current from flowing back, and the
diode D1 and the diode D2 also have a function of competing power
supply. For example, if the voltage supplied by the second power
supply terminal V2 is higher than the voltage provided by the first
power supply terminal V1, the second power supply terminal V2
ensures that the BMU is continuously in the operating state when
the BMU is in the operating state.
[0136] The related content of the protection capacitor, the filter
capacitor, and the filter resistor may be referred to the related
description in the above embodiments, and details are not described
herein again.
[0137] For example, as shown in FIG. 4, the protection capacitor in
the detection module P2 includes a fifth protection capacitor C9.
The filter capacitor includes a fifth filter capacitor C10. The
filter resistor includes a resistor R17. One end of the fifth
protection capacitor C9 is connected to one end of the resistor R7
connected to the fifth sampling point AD5, and the other end of the
fifth protection capacitor C9 is connected to the ground. One end
of the fifth filter capacitor C10 is connected to one end of the
resistor R17 and the fifth sampling point AD5, and the other end of
the fifth filter capacitor C10 is connected to the ground. The
other end of the resistor R17 is connected to the fifth protection
capacitor C9.
[0138] The processing module P3 is configured to: obtain a fifth
sampled data from the fifth sampling point; determine an on-off
state of the third sensing cable based on the fifth sampled data;
determine whether thermal runaway occurs in the battery pack based
on the on-off state of the third sensing cable and the battery pack
data.
[0139] The on-off state of the third sensing cable includes an open
circuit and a non-open circuit (ie, a normal path). The fifth
sampled data collected from the fifth sampling point is different
in the case where the third sensing cable is open circuited and not
open circuited. The on-off state of the third sensing cable may be
determined based on the fifth sampled data.
[0140] In some examples, a fifth open-circuit threshold range for
determining that the third sensing cable is open circuited may be
preset. The fifth open-circuit threshold range is related to the
voltage supplied by the first power supply terminal. If the thermal
runaway detection circuit further includes a sleep-wakeup module
P4, the sleep-wakeup module P4 further includes a diode, and the
fifth open-circuit threshold range is also related to the
diode.
[0141] In some examples, a fifth path threshold range for
determining that the third sensing cable is in path state may also
be preset. The fifth path threshold range is related to the voltage
provided by the first power supply terminal, the seventh voltage
dividing resistor set, and the eighth voltage dividing resistor
set. If the thermal runaway detection circuit further includes a
sleep-wakeup module P4, the sleep-wakeup module P4 includes a ninth
voltage dividing resistor set, and the fifth path threshold range
is also related to the ninth voltage dividing resistor set. If the
sleep-wakeup module P4 further includes a diode, the fifth path
threshold range is also related to the diode.
[0142] The processing module P3 is configured to: determine that
the third sensing cable is open circuited when the fifth sampled
data is within the fifth open-circuit threshold range; determine
that thermal runaway occurs in the battery pack when the third
sensing cable is open circuited and at least one parameter of the
battery pack data satisfies the fault condition within the preset
period. The battery pack data includes at least one parameter.
[0143] The parameters in the battery pack data and the fault
conditions may be referred to the related description in the above
embodiments, and details are not described herein again.
[0144] In some examples, the processing module P3 is configured to
determine that thermal runaway occurs in the battery pack when the
third sensing cable is not open circuited and at least one set of
parameters in the battery pack data satisfies the fault condition
within the preset period.
[0145] A set of parameters includes at least two parameters. At
least one set of parameters in the battery pack data and fault
conditions may be referred to the related description in the above
embodiments, and details are not described herein again.
[0146] It should be noted that if the fifth sampled data is neither
within the fifth open-circuit threshold nor within the fifth path
threshold, it may be determined that there is a fault at the
sampling port of the fifth sampling point.
[0147] If it is determined that there is a fault at the sampling
port of the sampling point, a prompt message about sampling fault
may be sent to prompt the vehicle controller to take corresponding
measures or prompt the persons related.
[0148] In some examples, the processing module P3 may be further
configured to send a thermal runaway warning message when it is
determined that the third sensing cable is not open circuited and
the battery pack data satisfies the fault condition.
[0149] The battery pack data includes the maximum voltage of a cell
in the battery pack during charging, the actual state of charge of
the battery pack during charging, and the charging current of the
battery pack during charging. The fault conditions include a
parameter that exceed the safety parameter threshold range.
[0150] Corresponding to specific parameters in the battery pack
data, the safety parameter threshold range includes a voltage
safety parameter threshold range, a state of charge safety
parameter threshold range, and a current safety parameter threshold
range.
[0151] That is to say, if it is determined that the third sensing
cable is not open circuited, the maximum voltage of a cell in the
battery pack during charging exceeds a voltage safety parameter
threshold range, the actual state of charge of the battery pack
during charging exceeds a state of charge safety parameter
threshold range, and the charging current of the battery pack
during charging exceeds a current safety parameter threshold range,
it may be predicted that thermal runaway is about to occur in the
battery pack. The thermal runaway warning message may be sent, so
that corresponding measures can be taken in advance to avoid
thermal runaway and further improve the safety of the battery
pack.
[0152] Corresponding to the thermal runaway detection circuit in
the above embodiments, the embodiments of the disclosure further
provides a thermal runaway detection method, which may be
specifically executed by the processing module. FIG. 5 is a
flowchart of a thermal runaway detection method according to an
embodiment of the disclosure. As shown in FIG. 5, the thermal
runaway detection method may include steps S101 and S102.
[0153] In step S101, thermal runaway detection data is
acquired.
[0154] In step S102, it is determined whether thermal runaway
occurs in the battery pack based on the thermal runaway detection
data.
[0155] The thermal runaway detection data includes battery pack
data and sampled data collected from sampling points. The sampling
point is disposed between two connected sets of voltage dividing
resistors.
[0156] In the embodiments of the present disclosure, the sensing
module in the thermal runaway detection circuit includes a sensing
cable, and the distance between at least a portion of the sensing
cable and the cell in the battery pack is less than the temperature
sensitive distance threshold, so that the state of the sensing
cable can be affected by the temperature of the cell in the battery
pack. When the sensing cable is affected by the temperature of the
cell, and the on-off state of the sensing cable will change, so
that the sampled data collected by the processing module from the
sampling point will change. The processing module may determine
whether thermal runaway occurs in the battery pack based on the
thermal runaway detection data so as to detect the thermal runaway
of the battery pack in time. As a result, the safety of the battery
pack can be improved.
[0157] The specific structure of the thermal runaway detection
circuit is different, and the specific implementation of the
thermal runaway detection method may also be different.
[0158] In some examples, FIG. 6 is a flowchart of a thermal runaway
detection method according to another embodiment of the present
disclosure. The thermal runaway method may be applied to the
thermal runaway detection circuit as shown in FIGS. 2 and 3, and is
specifically executed by the processing module. FIG. 6 is different
from FIG. 5 in that step S101 of FIG. 5 may be refined to step
S1011 of FIG. 6. Step S102 of FIG. 5 may be refined to steps S1021
through S1024 of FIG. 6. The thermal runaway detection method as
shown in FIG. 6 may further include step S103.
[0159] In step S1011, a first sampled data, a second sampled data,
a third sampled data, and a fourth sampled data are respectively
acquired from a first sampling point, a second sampling point, a
third sampling point, and a fourth sampling point.
[0160] The step S102 in the above embodiments may be refined to
determine an on-off state of the first sensing cable based on the
first sampled data and the second sampled data; determine an on-off
state of the second sensing cable based on the third sampled data
and the fourth sampled data; determine whether thermal runaway
occurs in the battery pack based on the on-off state of the first
sensing cable, the on-off state of the second sensing cable, and
the battery pack data.
[0161] In step S1021, if the first sampled data is within the first
open-circuit threshold range and the second sampled data is within
the second open-circuit threshold range, it is determined that the
first sensing cable is open circuited.
[0162] In step S1022, if the third sampled data is within the third
open-circuit threshold range and the fourth sampled data is within
the fourth open-circuit threshold range, it is determined that the
second sensing cable is open circuited.
[0163] In step S1023, if the first sensing cable and the second
sensing cable are both open circuited, and at least one parameter
in the battery pack data satisfies a fault condition within the
preset period, it is determined that thermally runaway occur in the
battery pack.
[0164] The battery pack data includes at least one parameter.
[0165] In step S1024, if it is determined that at least one of the
first sensing cable and the second sensing cable is not open
circuited, and at least one set of parameters in the battery pack
data satisfies a fault condition within the preset period, it is
determined that thermal runaway occurs in the battery pack.
[0166] A set of parameters includes at least two parameters.
[0167] In step S103, if it is determined that at least one of the
first sensing cable and the second sensing cable is not open
circuited, and the battery pack data satisfies the fault condition,
a thermal runaway warning message may be sent.
[0168] The battery pack data includes the maximum voltage of a cell
in the battery pack during charging, the actual state of charge of
the battery pack during charging, and the charging current of the
battery pack during charging. The fault conditions may include a
parameter that exceed a safety parameter threshold range.
[0169] In other examples, FIG. 7 is a flowchart of a thermal
runaway detection method according to yet another embodiment of the
present disclosure. The thermal runaway detection method may be
applied to the thermal runaway detection circuit as shown in FIG.
4, and is specifically executed by the processing module. FIG. 7 is
different from FIG. 5 in that step S101 of FIG. 5 may be refined to
step S1012 of FIG. 7. Step S102 of FIG. 5 may be refined to step
S1025 to step S1027of FIG. 7. The thermal runaway detection method
as shown in FIG. 7 may further include step S104.
[0170] In step S1012, the fifth sampled data is acquired from the
fifth sampling point.
[0171] The step S102 may be refined to determine an on-off state of
the third sensing cable based on the fifth sampled data; and
determine whether thermal runaway occurs in the battery pack based
on the on-off state of the third sensing cable and the battery pack
data.
[0172] In step S1025, if the fifth sampled data is within the fifth
open-circuit threshold range, it is determined that the third
sensing cable is open circuited.
[0173] In step S1026, if the third sensing cable is open circuited,
and at least one parameter in the battery pack data satisfies a
fault condition within the preset period, it is determined that
thermal runaway occurs in the battery pack.
[0174] The battery pack data includes at least one parameter.
[0175] In step S1027, if it is determined that the third sensing
cable is not open circuited, and at least one set of parameters in
the battery pack data satisfies a fault condition within the preset
period, it is determined that thermal runaway occurs in the battery
pack.
[0176] A set of parameters includes at least two parameters.
[0177] In step S104, if it is determined that the third sensing
cable is not open circuited and the battery pack data satisfies a
fault condition, a thermal runaway warning message is sent.
[0178] The battery pack data includes the maximum voltage of a cell
in the battery pack during charging, the actual state of charge of
the battery pack during charging, and the charging current of the
battery pack during charging. The fault conditions may include a
parameters that exceed a safety parameter threshold range.
[0179] In the above two examples, if the sensing cable is open
circuited, and at least one parameter in the battery pack data
satisfies a fault condition, it is determined that thermal runaway
occurs in the battery pack, the battery pack data includes one or
more of the following parameters:
[0180] a maximum temperature of a cell in the battery pack, a
temperature change rate of a cell in the battery pack, a difference
between the maximum temperature and a minimum temperature of a cell
in the battery pack, a minimum voltage of a cell in the battery
pack, a number of voltage sampling open-circuit faults of the
battery pack, a temperature sensing failure parameter, and a cell
monitoring communication failure parameter.
[0181] The maximum temperature of the cell in the battery pack, the
temperature change rate of the cell in the battery pack, the
difference between the highest temperature and the lowest
temperature of the cell in the battery pack, the minimum voltage of
the cell in the battery pack, The number of voltage sampling and
open-circuit faults of the battery pack, the temperature sensitive
failure parameters, and the battery monitoring communication
failure parameters.
[0182] The fault condition may include a parameter exceeding a
safety parameter threshold range or a parameter characterizing a
failure.
[0183] In the above two examples, if not all of the sensing cables
are open circuited, and at least one set of parameters in the
battery pack data satisfies the fault condition, it is determined
that thermal runaway occurs in the battery pack, the set of
parameters includes any of the following sets of parameters.
[0184] The set of parameters may include at least two parameters.
The set of parameters may include any of the following sets of
parameters: the minimum voltage of a cell in the battery pack, and
the maximum temperature of a cell in the battery pack; the minimum
voltage of a cell in the battery pack, and the temperature change
rate of a cell in the battery pack; the minimum voltage of a cell
in the battery pack, and the difference between the maximum
temperature of a cell in the battery pack and the minimum
temperature of a cell in the battery pack; the temperature change
rate of a cell in the battery pack, and the maximum temperature of
a cell in the battery pack; the temperature change rate of a cell
in the battery pack, and the difference between the maximum
temperature of a cell in the battery pack and the minimum
temperature of a cell in the battery pack; the number of voltage
sampling open-circuit faults of the battery pack, and the maximum
temperature of a cell in the battery pack; the number of voltage
sampling open-circuit faults of the battery pack, and the
temperature change rate of a cell in the battery pack; the number
of voltage sampling open-circuit faults of the battery pack, and
the difference between the maximum temperature of a cell in the
battery pack and the minimum temperature of a cell in the battery
pack; and the number of voltage sampling open-circuit faults of the
battery pack, and the temperature sensing failure parameter.
[0185] The fault condition may include a parameter exceeding the
safety parameter threshold range or a parameter characterizing a
failure.
[0186] In some examples, when the thermal runaway detection circuit
further includes a sleep-wakeup module, the above thermal runaway
detection method may further include the step of the sleep-wakeup
module sending a control signal to the power module of the battery
management unit if the battery management unit is in a sleep state.
The control signal is used to instruct the power module to control
the battery management unit to remain in the sleep state or switch
to an operating state.
[0187] In some examples, the above thermal runaway detection method
may further include the step of the processing module sending an
alarm signal to the vehicle controller when it is determined that
that thermal runaway occurs in the battery pack.
[0188] It should be noted that details for the steps of the thermal
runaway detection method may refer to the related description in
the embodiments of the thermal runaway detection circuit, which are
not described herein again.
[0189] An embodiment of the present disclosure further provides a
computer readable storage medium storing computer programs thereon,
which, when executed by a processor(s), may implement the thermal
runaway detection method in the above embodiments.
[0190] The embodiments of the above examples may be implemented in
various ways and should not be construed as being limited to the
embodiments set forth herein. Furthermore, the features,
structures, or characteristics described in the above embodiments
may be combined in one or more embodiments in any suitable manner.
However, those skilled in the art will appreciate that the
technical solution of the present disclosure may be practiced
without one or more of the specific details, or by employing other
methods, components, materials, and the like. In other cases,
well-known structures, material, or operations are not shown or
described in detail to avoid obscuring the main technical ideas of
the present disclosure.
[0191] It is to be understood that various embodiments in the
specification are described in a progressive manner. The same or
similar parts between the various embodiments may be referred to
each other, and each embodiment focuses on a different part from
other embodiments. For method embodiments, reference may be made to
the description for the circuit embodiments. The disclosure is not
limited to the specific steps and structures described above and
illustrated in the drawings. A person skilled in the art may make
various changes, modifications and additions, or change the order
between the steps after understanding the spirit of the disclosure.
Also, a detailed description of known techniques is omitted herein
for the sake of brevity.
[0192] Those skilled in the art should understand that the above
embodiments are exemplary rather than limitative. Different
technical features in different embodiments may be combined to
obtain beneficial effects. Other variations of the described
embodiments can be understood and practiced by those skilled in the
art upon studying the drawings, the specification and the claims
herein. In the claims, the term "comprising" does not exclude other
means or steps; the indefinite article "a" does not exclude a
plurality of; the terms "first", "second" are used to illustrate
names rather than to indicate any particular order. Any reference
numerals in the claims should not be construed as limiting the
scope of protection. The functions of the various parts in the
claims may be implemented by a single hardware or software module.
The presence of certain features in different dependent claims does
not indicate that these technical features cannot be combined to
achieve beneficial effects.
* * * * *